The invention relates to digital cameras and more specifically to a digital camera system that provides remote storage and image enhancement combined with an in-camera display device.
A digital camera captures an image of a particular subject using an imaging system that includes an optical lens and a photosensor array, such as a charged coupled device (CCD). The imaging system xe2x80x9ccapturesxe2x80x9d a set, or frame, of digital image data that represents a particular subject at the time that the frame is captured. Each frame of digital image data can be stored in a memory for subsequent viewing on a display, printing onto paper, or downloading to a computer system. Because of the inherent space limitations of a hand-held digital camera, memory capacity for storing frames of digital image data within the camera is limited.
In addition to having storage capability, hand-held digital cameras are able to process digital image data to enhance the resolution and overall quality of an image that is presented to a viewer. In order to perform increasingly complex image enhancements, additional processing capability is required on-board a hand-held digital camera, but because of the inherent space limitations of hand-held digital cameras, processing capability is limited.
Hand-held digital cameras are available in which a still image of a subject can be viewed from a display device located within the hand-held digital camera. In hand-held digital cameras with image display capability, the problems of memory and processing limitations are magnified.
One technique used to overcome the memory limitations of hand-held digital cameras is disclosed in U.S. Pat. No. 5,534,921, entitled xe2x80x9cCCD Digital Camera System With Selectable Memories,xe2x80x9d issued to Sawanobori. In the Sawanobori patent, a detachable memory card is inserted into a hand-held digital camera and digital image data is transferred to the memory card. When the storage capacity of the memory card is reached, the memory card can be removed from the camera and replaced with a new memory card. A concern with the Sawanobori technique is that the memory cards themselves have limited storage capacity. A second concern is that the memory cards must be manually replaced when memory capacity is reached, creating a delay and a distraction to the operator of a hand-held digital camera.
Another technique that is employed to address the memory limitations of hand-held digital cameras is disclosed in U.S. Pat. No. 5,402,170 entitled xe2x80x9cHand-Manipulated Electronic Camera Tethered To A Personal Computer,xe2x80x9d issued to Parulski et al. (hereinafter ""170). In the ""170 patent, an electronic camera is linked to a computer by a cable and an interface protocol is utilized to allow the camera to transmit image data over the cable and into a memory device of the computer. Disadvantages of the technique are that the hand-held digital camera must be xe2x80x9ctetheredxe2x80x9d to the computer by a cable in order to accomplish data storage and that the technique only allows data transfer in one direction, from the camera to the computer, eliminating the possibility of viewing previously stored images on the display device of the hand-held digital camera.
A technique for overcoming the memory limitations involving the wireless transmission of electronic image data from an electronic hand-held camera is disclosed in U.S. Pat. No. 5,666,159, entitled xe2x80x9cElectronic Camera System With Programable Transmission Capability,xe2x80x9d issued to Parulski (hereinafter ""159). In the ""159 patent, an electronic camera is detachably coupled to a portable computer that has a display module and a radio-frequency transmitter module. The system is able to transmit electronic image data to a selected base unit using standard wireless communications techniques. While the technique is intended to be used to send facsimile images of a subject to a fax machine, the technique can be adapted to allow corresponding facsimile image data to be stored in a properly equipped computer. A disadvantage of the technique is that image data is transferred in only one direction, from the camera/computer combination to a base unit.
Another example of a wireless transmission technique used to transmit electronic image data is disclosed in U.S. Pat. No. 5,475,441, entitled xe2x80x9cElectronic Camera With Memory Card Interface To A Computer,xe2x80x9d issued to Parulski et al (hereinafter ""441). In the ""441 patent, electronic image data is transmitted from an electronic hand-held camera with no display capability to a computer via a wireless transmission link. The computer that receives the data is relied upon to perform image processing, image data storage, and image display. While the ""441 patent provides a high speed interface for transferring image data from a hand-held camera to a computer, a disadvantage of the ""441 patent is that the hand-held camera does not have image display capability and the interface does not allow image data that is stored on the computer to be transmitted back to the hand-held camera for viewing.
What is needed is a hand-held digital camera system that has a built-in image display device and high capacity image data storage. In addition, what is need is a hand-held digital camera system that can display high quality images for viewing immediately after an image is captured.
A method and system allow a hand-held digital camera to have continuous access to large volumes of digital image data utilizing a bi-directional wireless communications link between a host computer and the camera. In an embodiment of the invention, imaging optics and a photo-sensor array capture image data that represents an image of a subject. A transceiver integrated into the hand-held digital camera transmits the image data to a host computer via a wireless communications link. The host computer stores the image data, or a copy of the image data, and retransmits the image data back to the hand-held digital camera via the wireless communications link. Once the image data is received by the hand-held digital camera, an electronic image representative of the image data is displayed by a display device that is integrated into the camera. The communications link between the hand-held digital camera and the host computer can transfer data at a sufficiently high rate to provide virtually real-time feedback to a camera operator.
In a preferred embodiment of the invention, when the image data is received at the host computer, the image data is processed by an image processor within the host computer in order to enhance the quality of the image data that was initially captured by the hand-held digital camera. Enhancements in the image data may include applying mathematical algorithms to generate greater pixel density or adjusting color balance, contrast, and/or luminance. Once the improved image data is generated by the image processor of the host computer, the host computer transmits the improved image data to the hand-held digital camera. The hand-held digital camera receives the improved image data and forms an enhanced electronic image that is displayed on the display device of the camera. The bi-directional communications link and the processing speed of the host computer enable virtually real-time feedback to a camera operator. The improved data may consist of image correction data or it may contain an entire array of image data. In addition, the improved image data may be made responsive to user-defined criteria that may include morphing, distortion, changes in perspective, and other artistic enhancements.
In addition to displaying images that have just been captured by the hand-held digital camera, the camera can display previously captured images by accessing image data that is stored in the host computer. For example, the hand-held digital camera can access and display an image that was captured the previous day, since the data is stored in the host computer.
An advantage of the hand-held digital camera is that the camera can display just-captured images in nearly real-time, while having continuous and wireless access to a large image data storage capacity that allows viewing of previously captured images. The hand-held digital camera also provides the capability of comparing captured images to images in an image database and displaying certain stored images that meet user-specified similarity criteria. In addition, stored global positioning system (GPS) data concerning camera position and even orientation can enable the display of previously captured images having similar associated attributes.
Another advantage is that processing performance required to display high quality images is not limited by the processing capability of the hand-held digital camera, but by the processing capability of the host computer. The processing capability of the host computer allows the host computer to improve captured image data well beyond the practical capabilities of a hand-held digital camera. Another advantage of the hand-held digital camera is that the camera does not require removable memory cards which must be frequently exchanged and the camera is not xe2x80x9ctetheredxe2x80x9d to a host computer by a data cable.